Firestore 雲功能更新所有文檔中的字段與參數

Question

我有一個 firestore 集合“ Messages ”，帶有一個布爾字段“ viewed ”和一個字段“ userToRef ”，其中包含一個coll:Users -reference。 我希望我的雲功能將coll:Message中所有文檔中的字段“ viewed ”更新為“ True ”，這些文檔在字段“ userToRef ”中具有與 URL 參數“ userRef ”相同的用戶引用。

但無論我做什么，它都會引發404-error ：

const functions = require('firebase-functions');
const admin = require('firebase-admin');

admin.initializeApp();

exports.allMsgOfUserRead = functions.https.onRequest((req, res) => {
  // Get the user reference from the request with the id of the document
  const strRef = req.query.userRef;
  const userRef = admin.firestore().collection('Users').doc(strRef);

  // Update the "viewed" field of all documents in the "Messages" collection
  // where the "userToRef" field matches the user reference
  return admin.firestore()
    .collection('Messages')
    .where('userToRef', '==', userRef)
    .get()
    .then(snapshot => {
      if (!snapshot.exists) {
        // Document does not exist, return an error response
        return res.status(404).json({
          message: `Messages to User not found ${req.query.userRef}`,
          code: 404
        });
      }

      snapshot.forEach(doc => {
        doc.ref.update({ viewed: true });
      });
      return res.json({
        message: 'Success',
        code: 200
      });
    })
    .catch(error => {
      return res.status(500).json({
        message: 'Error occurred',
        code: 500
      });
    });
});

我真的需要一個想法，為什么會這樣……謝謝！

Answer 1

我從未嘗試過編寫這樣的代碼，但我強烈懷疑當您使用admin.firestore().collection('Users').doc(strRef)作為搜索代碼中的鍵時您會得到什么 .where .where('userToRef', '==', userRef) 。

也許您想使用req.query.userRef代替？

return admin.firestore()
    .collection('Messages')
    .where('userToRef', '==', req.query.userRef)
    .get()
    ...

Answer 2

您不應在forEach()循環中執行一組對異步update()方法的調用。 您應該使用Promise.all() ，如下所示。 另外，請注意QuerySnapshot始終存在並且可能為空：使用empty屬性進行檢查。

exports.allMsgOfUserRead = functions.https.onRequest((req, res) => {
    // Get the user reference from the request with the id of the document
    const strRef = req.query.userRef;
    const userRef = admin.firestore().collection('Users').doc(strRef);

    // Update the "viewed" field of all documents in the "Messages" collection
    // where the "userToRef" field matches the user reference
    admin.firestore()   // <= No need to return here, since we don't return a Promise chain in an HTTPS Cloud Function
        .collection('Messages')
        .where('userToRef', '==', userRef)
        .get()
        .then(snapshot => {
            if (snapshot.empty) {
                // Document does not exist, return an error response
                res.status(404).json({
                    message: `Messages to User not found ${req.query.userRef}`,
                    code: 404
                });
            } else {

                const promises = [];
                snapshot.forEach(doc => {
                    promises.push(doc.ref.update({ viewed: true }));
                });

                return Promise.all(promises)
            }
        })
        .then(() => {
            res.json({
                message: 'Success',
                code: 200
            });
        })
        .catch(error => {
            res.status(500).json({
                message: 'Error occurred',
                code: 500
            });
        });
});

---

由於您的代碼中有一個if塊，我會使用async / await關鍵字以獲得更簡單和更清晰的代碼：

exports.allMsgOfUserRead = functions.https.onRequest(async (req, res) => {
    try {
        // Get the user reference from the request with the id of the document
        const strRef = req.query.userRef;
        const userRef = admin.firestore().collection('Users').doc(strRef);

        // Update the "viewed" field of all documents in the "Messages" collection
        // where the "userToRef" field matches the user reference
        const snapshot = await admin.firestore()
            .collection('Messages')
            .where('userToRef', '==', userRef)
            .get();


        if (snapshot.size === 0) {
            // Document does not exist, return an error response
            res.status(404).json({
                message: `Messages to User not found ${req.query.userRef}`,
                code: 404
            });
        } else {

            const promises = [];
            snapshot.forEach(doc => {
                promises.push(doc.ref.update({ viewed: true }));
            });

            await Promise.all(promises);

            res.json({
                message: 'Success',
                code: 200
            });
        }

    } catch (error) {
        res.status(500).json({
            message: 'Error occurred',
            code: 500
        });
    }

});

---

最后說明： QuerySnapshot很可能包含 0 或 1 個QueryDocumentSnapshot （只有一個用戶對應於特定的用戶引用，不是嗎？），因此您實際上不需要循環。 如果QuerySnapshot不為空，您可以使用snapshot.docs[0]獲取唯一文檔。